SOLUTION: Please help me!!! The area of 10 cm by 25 cm rectangle is doubled by what equal amount must each dimension be increased? assignment for tomorrow. help me asap!!

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Question 902111: Please help me!!!
The area of 10 cm by 25 cm rectangle is doubled by what equal amount must each dimension be increased?
assignment for tomorrow. help me asap!!

Found 2 solutions by ewatrrr, Theo:
Answer by ewatrrr(24785)   (Show Source): You can put this solution on YOUR website!
 
Hi,
.
A = (10cm)(25cm) = 250cm^2
Question States***
A = (10cm + x)(25cm + x) = 500cm^2
x^2 + 35x - 500 = 0 (Tossing out the negative solution for unit measure)
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=3225 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 10.8945417290014, -45.8945417290014. Here's your graph:

Answer by Theo(13342)   (Show Source): You can put this solution on YOUR website!
the area is increased by the square of the increase in the dimensions.

this means that, if the dimensions are increased by a factor of 2, then the area is increased by a factor of 2^2 = 4.

working backward, if the area is increased by a factor of 4, then the dimensions are increased by a factor of sqrt(4) = 2.

in your problem, the area was increased by a factor of 2.

using the rule shown above, this means that the dimensions must be increased by a factor of sqrt(2).

let's see if this rule holds.

your original area is 10 * 25 = 250 square units.

you multiply the area by a factor of 2 which means your new area is 500 square units.

you need to multiply your dimensions by a factor of sqrt(2) if the rule holds.

you will get:

10*sqrt(2)*25*sqrt(2) = 10*25*sqrt(2)*sqrt(2)= 10*25*2 = 500.

the rule works.

your solution is that each dimension must be multiplied by a factor of sqrt(2).



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